Telephony and Internet based environments today drive introduction of IP/IT based services opening virtually unlimited opportunities, e.g., for multimedia communication services with content access, application sharing and whiteboarding type of applications. Here, the difference between existing telecom services will be significant and attractive for efficient communication.
Already today, different terminals with different capabilities, e.g., voice, video, data, multimedia, etc. are available in the market place. These different terminals are operated in different communication networks, e.g., POTS, ISDN, GSM using network services like HSCSD and GPRS and also different communication protocols, e.g., for multimedia the ITU-T H.323 and the IETF Session Initiated Protocol SIP exist.
However, an increasing number of available services, e.g., voice, data, multimedia will be provided through a plurality of different terminals being used for the different communication processes. The more terminals an end user will use the higher the effort to handle these different terminals will be. In an extreme case it could be possible that one end user has to handle a plurality of different end terminals, e.g., a mobile telephone for a voice call and a video terminal for video reception during a single communication session. This situation becomes even more severe in the case two persons communicating with each other use different groups of end terminals. Currently no solution is available to facilitate the handling and interfacing between different communication capabilities on both sides of a communication link.
These conventional application scenarios are very inconvenient for subscribers since in a communication session separate call setup is requested for each type of communication. Subscribers using different terminals have to initiate a voice communication link at the beginning of the communication session and to set up data and/or video links as far as necessary afterwards. However, what is missing is support for-the coordination of the different setup procedures and for the control of the communication session. Also, a subscriber initiating a communication session does not have any knowledge on what type of terminals the other subscriber will use. Therefore it is impossible to achieve an efficient communication session setup and to address multiple terminals using only a single identifier. In other words, all the burden is put on the subscribers.
Further, the option to bring new types of applications to GSM, GPRS, UMTS or Internet users implies the need to introduce a common control for the different media streams as well as for conversion between, e.g., speech, data and video in a single circuit or packet switched bearer. Still further, no approach to overcome problems like long delays over radio, narrow bandwidth, long network delays, IP protocol overhead, lack of an efficient mechanism to prioritise real-time traffic over best effort traffic, etc. exist so far.